Clinical pharmacy question on atrial fibrillation? -

commenton this case: CC: SB is a man, age 62, who presents to the emergency department with light headache, palpitations, and shortness of breath, which have lasted for 2 days. Problem list 1. atrial fibrillation 2. hypertension 3. hyperlipidemia 4. chronic renal failure Problem 1. Atrial fibrillation S: patient complaints of dizziness, SOB, palpitations. O: BP 110/65, HR 146, pulse irregular irregularly, ECG: atrial fibrillation. A: the cause of SB’s atrial fibrillation (AF) is most likely his history of childhood rheumatic heart disease. However, AF may occur in patient with hypertension as well. On echocardiogram, the atria are enlarged and mild hypertrophy of left ventricle is noted. These enlarge are long-term results of hypertension. Rarely is atrial fibrillation a cause of mortality, but it can be significant cause of morbidity. The detrimental effects of AF are hemodynamic compromise and thromboembolic events. Both can be prevented by returning the heart to normal sinus rhythm. Direct current (DC) cardioversion is the most effective method to convert AF to normal sinus rhythm (NSR) with an 85 to 90 % success rate. Chemical conversion with antiarrhythmic has lower success rate, especially after AF as been present for longer than 24 hrs. SB is at risk for thromboembolic event at the time of cardioversion, even though no thrombi were seen on the echocardiogram. The risk for emboli is significant when the duration of AF is 2 days or more, because atrial function may not return for up to 2 weeks even after normal sinus rhythm is restored. The current standard of practice is to use anticoagulant for 3 weeks before cardioversion and for 4 weeks after in patient at risk for clot formation. In the interim, because SB is asymptomatic, the ventricular rate must be controlled to maintain adequate cardiac output. Digoxin, B- blockers, and calcium-channel blockers are all useful in controlling the ventricular rate by slowing conduction through the AV node. Digoxin is not the best choice in SB because the potential for toxicity if renal function continues to deteriorate. Furthermore, digoxin is not effective in controlling AF during exercise, and SG has reported palpitations during exercise. B-blockers could be used but there is the potential for decreased exercise tolerance. Calcium-channel blockers have been reported to have no effect or improve exercise tolerance in patients with AF. Calcium-channel blockers may also be used to control hypertension, potentially allowing the removal of other antihypertensives from the regimen SB is currently following. P: start either verapamil or deltiazem IV to control ventricular rate. Initiate anticoagulation with warfarin. Plan a direct current cardioversion in 3 weeks. Questions: Should SB be given an antiarrhythmic agent before cardioversion to maintain sinus rhythm? Should SB be loaded on warfarin to achieve steady state anticoagulation faster?

IV diltiazem is the drug of choice since the patient is symptomatic; there is no warfarin quot;loadquot;. They are started on oral warfarin and it takes several days for a theraputic blood level to be reached, thus the delay in cardioversion.

the NICE guidelines on AF can help you answer this question: think he should be loaded on warfarin - this is the regime for reaching equilibrium quickly since you want to cardiovert ASAP. because he has had symptoms for 2 days so there is a risk that there is a thrombus in his heart ready to launch off to somewhere important as soon as normal rhythm is established. doubtful about the first question i d be looking at controlling his rate i think until DC cardioversion is appropriate but i may easily be wrong.